1. Field of the Invention
This invention relates to a closed loop dispensing system and more particularly to a dispensing system for dispensing corrosive liquid chemicals or dangerous medical liquid products which are typically drawn from the upper end of a container, such as a bottle or the like, to a mixing machine or the like. In the instant invention, the container is inverted with the liquid product being drawn from the lower end thereof by vacuum or by gravity flow.
2. Description of the Related Art
Corrosive liquid chemicals and dangerous medical liquid products are typically contained in a container such as a bottle or the like and are frequently dispensed therefrom to a mixing machine. Normally, a cap is placed on the bottle with a dip tube extending therefrom downwardly into the interior of the bottle for drawing the liquid upwardly thereinto. Normally, a dispensing tube extends from the cap to a mixing machine or some other piece of equipment which creates suction in the dispensing tube to draw the liquid from the interior of the bottle. In some prior art devices, when the suction or vacuum is removed from the dispensing tube, backflow may occur. Further, when the cap is removed from the bottle, backflow from the dispensing tube may also occur. Additionally, when the cap is removed from the bottle, liquid residue in the bottle may spill therefrom. Additionally, the conventional prior art systems normally do not prevent the re-use of the bottle which is prohibited in some cases. Yet another disadvantage of the prior art is that a reliable and efficient venting means for the bottle is not normally provided for relieving vacuum pressure from within the bottle. The system of the co-pending application solved the problems associated with the prior art devices or systems.
While the system of the co-pending application works extremely well when the container is in its normal upright condition, the system may not perfectly function when the container of the co-pending application is inverted. When the container or bottle of the co-pending application is inverted, the liquid in the container is drawn or discharged from the normal upper end of the container but which is the lower end of the container in the inverted position. In such a position, the venting membrane, which would normally permit ambient air to replace the liquid in the container as the liquid is discharged from the container, may become “clogged” due to the liquid coming into contact therewith and crystallizing thereon. If air is not permitted to enter the container as the liquid is drawn therefrom, a partial vacuum is created in the upper end of the inverted container which will interfere with the discharge of the liquid therefrom.